The 1000 year old city once covered an area the size of greater London and was the imperial capital of the Khmer Empire, which at its height ruled parts of modern day Laos, Thailand, Vietnam, Burma and Malaysia. Angkor, which was built between the ninth and 12th centuries, is thought by archaeologists to have been the largest pre-industrial city in the world, stretching over 1010km2.
The core of the city comprised a series of elaborately carved temples, the most famous of which is Angkor Wat, the largest Hindu temple complex in the world. It was built during the reign of Kind Suryavarman II in the 12th century and each of the carved sandstone blocks used to construct the temple and surrounding monuments were up to one metre across and weighed 1.6 tonnes.
Because Angkor Wat was built in the reign of a single king – 35 years – archaeologists have long pondered how the five million tonnes of sandstone used to build the city’s temples were transported from quarries at the base of nearby Mount Kulen. By all estimates, with the technology available to them at the time, the Khmers should have completed the work in hundreds of years.
It had previously been speculated that the sandstone blocks must have been dragged over land from Mount Kulen to a river that carried them 35km to Tonlé Sap Lake, rafted another 35km along the lake, then sailed up the Siem Reap River for another 15km, against the current, to the construction site in Angkor – in all a round trip spanning up to 90km.
However, Professor Etsuo Uchida and his colleague Ichita Shimoda, from the department of resources and engineering at Waseda University in Tokyo, have now produced evidence that provides a much simpler explanation.
Mindful that the Khmer Empire used canals as a means of transportation, Uchida and Shimoda turned to satellite images to see if there could have been an alternative route. They found traces of a 34km long network of canals that lead directly from the foot of Mount Kulen to the Angkor ruins.
Field surveys have confirmed the archaeologists’ findings. Researchers found some canal remnants still contained water, while others had dried up or disappeared beneath roads. They also discovered large sandstone blocks at various points along the route where the blocks would have fallen off rafts in transit as well as 50 new quarries along the canal route where stones matching those of the temples had been dug out.
“These canals were constructed specifically for the transportation of sandstone blocks,” Uchida explained. “Compared to the previous transportation route proposed, this new route saves so much time. This canal is almost the shortest route and makes us consider that the Khmer people conducted the construction of the temples systematically and very effectively.”
In turn, this far more efficient route would have sped up the construction process. “I estimate that the construction of the canals took only a few years,” Uchida added. “[The Khmers] probably used boats or rafts to carry the blocks. Because it is not necessary to go upstream in the Siem Reap River, it seems that the sandstone blocks were transported efficiently by this route.”
The new route also adds credence to the theory that the Khmer kingdom declined because of ecological failure. Population growth placed the society’s system of canals, reservoirs and paddy fields under massive strain. To adapt to the burgeoning population, trees were cut down from the Kulen hills and cleared out for rice paddies. That contributed to rain run-off carrying sediment to the canal network, stifling the society’s lifeline.
Sources: Telegraph Media Group, Mail Online, New Scientist